The present invention relates to a supporting mechanism for a print head, a printer and a control method of a printer, in particular, to a supporting mechanism for a print head in a printer that performs printing while transporting a recording medium by rotationally driving a platen roller in a state that the recording medium is nipped and pressed between the print head and the platen roller, a printer comprising the supporting mechanism for the print head, and a control method of the printer.
There is a printer including a print head and a platen roller which is disposed so as to face the print head. The printer performs printing while transporting a recording medium by nipping the recording medium between the print head and the platen roller. The printer sometimes goes into a standby state under a condition that the recording medium is nipped between the print head and the platen roller and a long time may have elapsed under a condition that the recording medium is pressed against the print head. In such the printer, when printing is performed on a recording medium which is liable to stick under the pressed condition, such as a recording medium having a printing face applied with a coating, there is a possibility that the recording medium is stuck to the print head in a case where the recording medium is left in the standby state for a long time period.
JP-A-2006-334858 discloses a thermal printer that performs an operation for eliminating the sticking which occurs due to a state in which a recording medium (a label) is pressed against a print head (a thermal head) for a long time period. In the thermal printer, when a printing standby state continues for a predetermined time period or more, a control of rotationally driving a platen roller in backward and forward directions under a condition that the print head is fixed is performed, and thereby the recording medium stuck to the print head is repeatedly pulled back and forth along a transporting direction of the recording medium so as to be peeled from the print head.
JP-A-2006-334858 discloses a configuration in which the recording medium is to be moved in the backward and forward directions under a condition that the print head is pressed and fixed against the platen roller, and the recording medium is peeled from the print head by a shear force. However, in a case where a recording medium is strongly stuck to the print head, a shear force necessary for peeling the recording medium from the print head exceeds a rotational driving force of the platen roller by a conventional motor and is beyond a range of a transmission performance of a force due to friction or the like between a conventional platen roller and the recording medium. Therefore, there is a possibility that the platen roller slips and is not able to transport the recording medium. Consequently, the recording medium is not able to be pulled by a sufficient force so that there is a possibility that the sticking is not eliminated.